Field
The field relates to antifouling water treatment agents and repellent devices, particularly for treating or preventing infestation of mollusks such as zebra or quagga mussels.
Description of the Related Art
The invasive species of dreissena polymorpha (zebra mussels) and Dreissena rostriformis bugensis (quagga mussels) were first reported in the US in 1988, according to the USGS. Since 1988 the spread has been rapid in spite of control efforts. (Benson, A. J. 2011. Zebra mussel sightings distribution. Retrieved Oct. 29, 2012 from http://nas.er.usgs.gov/taxgroup/mollusks/zebramussel/zebramusseldistribution.aspx.) The annual costs to address this issue were estimated several years ago at 267 million dollars per year (Environ Manage. 2007 July; 40(1):105-12. Epub 2007 May 24.) This cost makes the control of these aquatic invasive species an economically important process.
Conventional control methods include heat, chemicals such as chlorine, and use of surface coatings. The immature mussels, called veligers, attach to some surfaces much more easily than others. For instance, wood and cotton rope are colonized much faster than metals. However, even metal surfaces may be colonized in time. A method of continuously repelling both adult mussels and veligers is needed.
US Pat. Appl. No. 2010/0307978 provides an apparatus and method for contaminant removal from an aqueous solution. A permeable reactive barrier and an effective method of removing contaminants from water using adsorbent powders, such as zero valent iron particles, adhered throughout a reticulated foam structure are provided. These contaminants can include, but are not limited to: selenium, perchlorate, chromates, halogenated organic compounds, aluminum, lead, copper, technetium and arsenic. The zero valent iron apparatus exemplified therein does not repel or prevent mollusk infestation.
Cuprous oxide and zinc oxide, which are commercially used antifoulants, function by releasing heavy metals, i.e., copper and zinc, a harmful toxin, especially in the marine environment.
It would be helpful to the field to overcome the toxicity issues related to antifouling agents, while maintaining the effectiveness of such treatments.